Today I Learned

[Tom.G]

Today I learned that not all piston engines have a wrist pin (piston pin). There are apparently radial aircraft engines where the connecting rod is firmly attached to the piston and the whole cylinder rocks! Who would'a thought that was more convenient?

See this post for a sketch: https://www.physicsforums.com/threads/radial-piston-input-torque.943080/

 

[CWatters]

At school I built a steam engine that worked that way. When the cylinder was in one position a hole in the side wall lined up with an inlet hole, when it rocked the other way the same hole lined up with an exhaust hole. All very simple if not exactly efficient. On mine the pivot was near the middle of the cylinder rather than at the top.

The boiler was a powdered milk tin. No separate safety valve. If the pressure got too high the lid blew off sending boiling water into the air/face.

 

[Buzz Bloom]

TIL (actually a few days ago) a new word: kakistocracy.
https://en.wikipedia.org/wiki/Kakistocracy

The earliest usage of the word dates to the 17th century, in Paul Gosnold's A sermon Preached at the Publique Fast the ninth day of Aug. 1644 at St. Maries.​

The sermon applied the term to Nero. The following are some references to later uses.

Usage of the word was rare in the early part of the 20th century, but it regained popularity in 1981 with criticism of the Reagan administration.

In November 2016, the word became commonly used by critics of Trump, a man who had never held any public office, after he was elected President of the United States and began to announce his appointees.​

 

[Drakkith]

Today I learned that honeybees are apparently very good at hiding. One got into my apartment, probably by crawling underneath the front door, and buzzed around for a bit. Before I could get the broom and shoo it back outside, it went behind my desk and completely disappeared! I have no idea where it may be and I only hope I don't get a stinging surprise in the near future.

 

[fresh_42]

Today I learned that honeybees are apparently very good at hiding. One got into my apartment, probably by crawling underneath the front door, and buzzed around for a bit. Before I could get the broom and shoo it back outside, it went behind my desk and completely disappeared! I have no idea where it may be and I only hope I don't get a stinging surprise in the near future.

Mine (surprise) has been in a toe ... It hurt twice, because I like bees.

 

[Ibix]

Today I learned that there is a thing called a "lithophone". It's like a xylophone, but instead of the bars being made of wood they are made of stone - slate and granite in this particular case. I had no idea you could make a musical sound from a stone, let alone play a tune.

I was so surprised I didn't make any rock music jokes.

 

[jtbell]

Today I learned that the latest trend in home decorating is to turn your books "backwards" on your bookshelves so their spines face towards the back of the shelf and the page-ends face outwards. This makes for a more uniform look, but also makes it rather difficult to find a specific book if you actually want to read it.

https://inews.co.uk/culture/backwards-books-maddest-interior-trend-2018/

A Google search for "backwards books" turns up lots of pictures of this sort of thing.

 

[fresh_42]

Today I learned that there is a thing called a "lithophone". It's like a xylophone, but instead of the bars being made of wood they are made of stone - slate and granite in this particular case. I had no idea you could make a musical sound from a stone, let alone play a tune.

I was so surprised I didn't make any rock music jokes.

And I thought this was a lithophone:

Source

 

[Tom.G]

I noticed the lithophone pictured uses quinary rather than decimal -- perhaps due to the limited number of fingers available?

 

[Drakkith]

I noticed the lithophone pictured uses quinary rather than decimal -- perhaps due to the limited number of fingers available?

Huh... I thought it used an evolution of early quaternary...

 

[kyphysics]

This might leave Russ Watters and NTL2009 reeling , but today I learned that Dave Ramsey's financial principles are taught in 30% of U.S. secondary schools.

This might increase in the future, as Ramsey is America's most listened to financial "guru." Even though I don't agree with him on some things, I do think it's great that the solid stuff he teaches in areas of agreement ARE being taught to young kids.

I wish we had an investment class when I was a kid that taught me that if I invested $5 a day for 20 years (the price of a single Star Bucks drink!) and NEVER put in another dime of my money after that into that investment retirement account, then I'd be a millionaire about 15 years later.

Just a few bucks a day...just a few bucks a day...and let compound interest take over with time.

He says that if you're not a millionaire in America with several decades of working experience, then you're a loser (barring any tough life circumstances like being handicapped, a victim of racism, etc.)! Harsh words. But he says it's easy if you just save your money, invest early, and let compound interest take over.

I want to be a millionaire with that $5/day plan!

 

[fresh_42]

I want to be a millionaire with that $5/day plan!

Have you actually done the calculation with current interest rates and average inflation or do you just trust some guru? You sound like the latter.

 

[kyphysics]

Have you actually done the calculation with current interest rates and average inflation or do you just trust some guru? You sound like the latter.

Not sure if it's current (2016 figures given), but he employs MIT, Stanford, etc. mathematicians, actuaries, accountants, etc. to do his "math work" for him, as he's talked about on the show.

They could be wrong. But, I trust these highly trained, professionally licensed guys, though. He'll often say something like: "My team crunched the numbers and gave me this total...I'm not a geek like them."

 

[fresh_42]

Not sure if it's current (2016 figures given), but he employs MIT, Stanford, etc. mathematicians, actuaries, accountants, etc. to do his "math work" for him, as he's talked about on the show.

They could be wrong. But, I trust these highly trained, professionally licensed guys, though. He'll often say something like: "My team crunched the numbers and gave me this total...I'm not a geek like them."

This attitude is the first step to get ripped off.

 

[kyphysics]

This attitude is the first step to get ripped off.

True. I agree to some extent (a very good warning - one Ramsey would endorse too). Except, we trust people in life all the time, who are respected, highly trained, and have no history of ripping people off (like a Robert Kiyosaki, who is a financial industry charlatan). ...Although, this is a check-able area for the average citizen (don't need a Ph.D. to do it), so you're right in a way too.

I am curious, though, if those figures hold up. We should probably talk about it in the relevant financial thread (I have one started, but there are others in place on this forum too), however, if you're interested.

Also, you can use the SEC's government compound interest calculator to do some of this basic stuff. It's a .gov site.

 

[kyphysics]

Not sure if it's current (2016 figures given), but he employs MIT, Stanford, etc. mathematicians, actuaries, accountants, etc. to do his "math work" for him, as he's talked about on the show.

They could be wrong. But, I trust these highly trained, professionally licensed guys, though. He'll often say something like: "My team crunched the numbers and gave me this total...I'm not a geek like them."

Scratch the MIT, Stanford, etc. part...I'll have to look up the episode where he talks about his team, since I don't know if those are the actual schools/pedigree of his staff members (I think I vaguely remember something like that...). Don't want to give false info. and want to be accurate.

He has talked about his team and their background before, though, but more as a way to jokingly tell us he's not a "nerd" like them.

 

[mfb]

You need 13% interest rate for that. Forget it.

With 10% interest rate you end up with $480,000. If we assume 2% inflation these $480,000 in 35 years are worth as much as $237,000 today.
With 5% interest rate you end up with $131,000. If we assume 2% inflation these $131,000 in 35 years are worth as much as $65,000 today.

Sure, there are investments where you become a millionaire. There are even investments where $1800 initial investment ($5/day for a year) can make you a billionaire in this time frame. But that needs an extraordinary amount of luck.

Saving money and waiting for compound interest is a good idea. But you won't become a millionaire just by saving $5/day for 20 years and then waiting for 15 more.

 

[Drakkith]

For Rubik's Cube fans, today I learned that there exists a 4D version of the Rubik's Cube. Obviously we can't make a physical 4D Rubik's Cube, but there is software which will generate the puzzle that you can solve. One such software is Magic Cube 4D. In addition to extending a Rubik's Cube into the 4th dimension, the program will generate much larger cubes (up to 8 cubes of 9x9x9) along with entirely different shapes. Good luck and happy solving!

 

[Buzz Bloom]

TIL

In fact, nobody knows how to actually calculate the entropy for a generic gravitational system.

This quote is from
https://www.physicsforums.com/threads/entropy-and-contracting-universe.943975/#post-5973770 .

 

[DrGreg]

Today I learned why uppercase and lowercase letters are called "cases".

It goes back to ancient times, when I was a boy and fonts weren't files on a computer, but were lumps of metal stored in compartments of a shallow wooden drawer or case. Typically capital letters were put in the case above and non-capitals in the case below.

Source: Letter case

 

[Tom.G]

Typically capital letters were put in the case above and non-capitals in the case below.

Thus making the more used non-capitals closer at hand.

 

[mathwonk]

i learned the topological cohomology of the punctured topological neighborhood of a singularity on a complete intersection variety over the complex numbers, equals the etale cohomology of the spectrum of the henselization of the local ring of the variety with the maximal ideal removed. (This was a conjecture I had generated to attempt to explain a remark Mumford made about the first example he gave of a prescheme, something I am trying to learn by reading his "red book" of algebraic geometry.)

 

[DennisN]

Today I learned that a three feet drop to the floor does not necessarily destroy a 3 TB external hard drive.
(I accidentally pulled on a power cord that was connected to the drive )

 

[Tom.G]

Today I learned that a three feet drop to the floor does not necessarily destroy a 3 TB external hard drive.
(I accidentally pulled on a power cord that was connected to the drive )

Don't be so sure. There may be just a tiny flake off the disk somewhere but it only takes one to start a failure cascade.

If it was powered off at the time you have a fair chance of no damage. Of course it all depends a lot on the surface it hit, in what orientation, and from how high.

If it was spinning, copy everything immediately, even before doing any tests, and use it only as a scratch disk. If you continue using it, you may want to run full-surface diagnostics on it occassionally over the next few hundred hours of running time. Do not count on the self diagnostics or error reporting, they are useful for tracking the wearout of the drive but can not be counted on for early head crash detection. I've even had "Factory Refurbished" drives fail full surface scans when the built-in self test shows a practically new drive.

Good Luck!
Tom

 

[DennisN]

Don't be so sure. [...] Good Luck! Tom

Thanks a lot! Now I got a bit nervous , but I will follow your advice!

Edit, HDD Fall Info:
Landing surface: Wood floor
Powered on or off: I don't know. It was on, but I pulled on the power cord itself. I think the HDD was probably on when it hit the floor.
Spinning: No, I don't think so.

 

[Borg]

You might want to at least run chkdsk on it.

 

[DennisN]

You might want to at least run chkdsk on it.

Will do, thanks!

 

[OCR]

Today I learned that a three feet drop to the floor does not necessarily destroy a 3 TB external hard drive.

Don't be so sure.

Interestingly, about a week ago, I watched a video about that...

Data Recovery On A Dropped 3TB Seagate Hard Drive

.

 

[Ibix]

Today I learned that Admiral Villeneuve, who commanded the French/Spanish forces at the Battle of Trafalgar to a devastating loss, was captured and returned to France after giving his parole. He died on his way back to Paris from six stab wounds to the chest, recorded as suicide.

 

[epenguin]

i learned the topological cohomology of the punctured topological neighborhood of a singularity on a complete intersection variety over the complex numbers, equals the etale cohomology of the spectrum of the henselization of the local ring of the variety with the maximal ideal removed.

Gosh! I didn't know that either!

 

[epenguin]

That Katherine Hepburn and Audrey Hepburn were not related.

 

[jim hardy]

That Katherine Hepburn and Audrey Hepburn were not related.

You mean they aren't Mother-Daughter?

 

[fresh_42]

You mean they aren't Mother-Daughter?

Nope. Not even sisters, aunt and niece, nothing.

 

[jim hardy]

Well ! There's one more thing i used to know for sure that just isn't so !
Thanks !

 

[fresh_42]

As of 2007, she [Audrey Hepburn] and Katharine Hepburn are the only "Best Actress" Oscar-winners to share a last name. Of course, they are not related.

http://www.imdb.com/name/nm0000030/bio?ref_=nm_ov_bio_sm